Instant food powders, such as powdered dessert mixes, which are designed to be combined with milk or water in order to obtain a viscous food, typically contain a pregelatinized starch ingredient. This starch is used primarily as a thickening agent in such products as powdered, instant pudding mixes. To date, tapioca starch has been a starch of choice as it inherently possesses a clean flavor and has other physical properties (i.e. a low gel temperature) which makes it particularly suitable for use in instant pudding mixes.
Tapioca starch is a raw material which is obtained primarily from southeast Asia and, as such, a reliable and economical supply of tapioca starch may be disrupted by various political or climatical events. Dent cornstarch is a material which is in abundant supply in the United States and is a relatively inexpensive commodity. However, dent cornstarch possesses a flavor which has been characterized as "woody" or "corny" and an undesirable odor. Dent cornstarch also has a relatively-high gel temperature. These negative characteristics are especially detrimental when it is desired to produce a pregelatinized dent cornstarch for use in instant pudding mixes.
Dent cornstarch has a gelation temperature of approximately 82.degree. C., as compared to tapioca starch which has a gelation temperature of 69.degree. C. This higher gel temperature for cornstarch makes it more difficult to cook as compared to tapioca starch. While it is known to reduce the gelatinization temperature of starch by chemical modification, such as hydroxypropylation, these efforts have not previously produced a pregelatinized dent cornstarch which has the ability to build viscosity and impart a desirable texture to an instant pudding in the same manner as is possible with more expensive starches such as tapioca and waxy maize. The apparent low capacity of pregelatinized dent cornstarch to build viscocity necessitates the use of additional starch material, as compared to tapioca and waxy maize starch, which further compounds the problems of off-tastes, off-odors and adverse textural impact which are inherent with dent cornstarch.
Various techniques are known to the art for treating and/or modifying cornstarch. For instance, U.S. Pat. No. 4,477,480 to Seidel et al. discloses a process for removing off-tastes from cereal starches such as cornstarch. U.S. Pat. No. 4,431,800 to Leusner et al, discloses a process for hydroxypropylating various starches, including cornstarch, in order to improve the physical characteristics related to the starch's performance as a thickener in products such as puddings. U.S. Pat. No. 4,280,851 to Pitchon et al, discloses a method and apparatus for producing spray-dried, pregelatinized starches, including cornstarch, wherein a starch slurry is sprayed into a nozzle cap where the starch particles are gelatinized. Thereafter, the gelatinized particles are dried, such as in a spray drying tower.
Up to the present time, however, there has not been available either economically-produced, pregelatinized cornstarch or pregelatinized cornstarch which is suitable for use in powdered instant food products, such as instant pudding mixes.